1. Field of the Invention
The present invention relates to well completion methods and apparatus. More particularly, the invention relates to methods and apparatus for engaging a downhole latching and anchoring assembly in a well and sequentially or simultaneously landing a well head into position without the intermediate removal of the tubing string from the well.
2. Background of the Related Art
Subsea well completions and workover operations can be extremely expensive to perform because of the complexity, size and inaccessibility of the well bore. Typically, a well head or well control valve complex is anchored to casing located on the sea bottom. A floating drilling platform or drilling ship having a position holding propulsion system positions the derrick above the well borehole and maintains the derrick and draw works in one position while the completion or well workover is taking place. Such equipment is very costly both in terms of capital investment and in terms of shielded labor trained in its usage. Such units, depending upon size, location of the well, etc. can cost one million dollars per day or more to operate. It is, therefore, desirable to minimize the time on location of such units during the drilling or work over of a subsea well.
Typically during a workover or reinstallation of a well completion system in a remote subsea well, at least two tubing runs are required. For example, using the current methods of workover or re-completion, a first tubing run is made into the borehole to xe2x80x9clandxe2x80x9d or secure an anchor seal assembly into the Bottom Hole Assembly (BHA) which has been left in place during the workover. This first tubing run also serves to determine the exact position of the tubing hanger in relation to the BHA. Then, the well tubing is at least partially pulled out of the hole in order to allow a subsea well head tubing hanger to be positioned correctly in the tubing string and a second tubing run is then made to xe2x80x9clandxe2x80x9d the anchor seal assembly and the subsea tubing hanger. Risks are involved in disengaging the anchor seal unit from the downhole packer in the BHA as the seal unit could accidentally be damaged in the process. This could require the entire seal unit to be removed from the well for replacement, essentially starting the process over.
It is, therefore, apparent that methods and apparatus for eliminating such multiple tubing runs into the well and to accomplish both landing an anchor seal unit and a subsea wellhead tubing hanger in a single tubing run in the well would provide both cost saving and safety advantages to operations in the industry.
One embodiment of the invention generally provides a space-out compensating downhole well tool and a method for its use. The apparatus and method of the invention allow for sequential or simultaneous (in a single tubing run) landing an anchor seal assembly and landing a tubing hanger into a subsea well head or control valve complex.
In one aspect, the tool includes an outer body fixable in a well and an inner body selectively allowing the tubing string to move between a first and second position in the well in order to properly locate a tubing hanger in a fixture after the outer body has been fixed in the well.
In another aspect, a well tool is provided which includes a polished bore receptacle, a lockout block having coil springs which urge the lockout block into contact with a thread profile, such as a thread form or other ratchet mechanism, on the tubing above the tubing seal assembly and a lockout block housing having a dog clutch mechanism on the lower end of the tool. The well tool can be run in on the tubing string later used for production of hydrocarbon from the well.
In another aspect, the invention provides a tool having two or more lockout blocks in one or more lockout block housings to enable telescoping of the tool and to insure that at least one of the lockout blocks engages a tubular body member actuation. The tubular body member may be one or more pipe joints having thread forms formed on the external surface thereof. The lockout blocks preferably have mating thread forms to engage the thread forms on the tubular body member on actuation. A single lockout member or multiple lockout members can be used to lock the lockout blocks into engagement with the tubular body member.